Japanese Patent Application No. 2000-277811, filed Sep. 13, 2000, is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to an electro-optical device, a method of driving the electro-optical device and an electronic instrument.
2. Description of Related Art
In an active matrix type TFT (Thin Film Transistor) liquid crystal device, for example, a data-line drive circuit converts RGB data to an analog signal which is in turn supplied to a plurality of data lines in the liquid crystal panel as data signal voltage. The individual pixels that correspond to selected scan lines are charged with the data signal voltage that is supplied to each of the data lines from the data-line drive circuit. The liquid crystal device selects a scan line from one that is, for example, closer to the data line drive circuit in one frame period. In this case, the closer to the end of the frame period, the farther the distance from the data-line drive circuit to a pixel to be charged becomes. This is more prominent as the liquid crystal screen gets larger.
Particularly, as the liquid crystal panel of the liquid crystal device becomes larger, the interconnection resistance and the interconnection capacitance become greater, thus increasing the influence of the interconnection delay on the supply of the data signal voltage to the data lines.
FIG. 21A shows a simple T type or xcfx80 type model of the interconnection delay. The model in FIG. 21A includes a power source 300 equivalent to the data-line drive circuit of a liquid crystal device, a line L equivalent to a data line and having parasitic resistances R1 to R3 and parasitic capacities C1 to C3 of the data line and pixels.
FIG. 31B shows chronological changes in voltages charged in the capacitors C1 to C3 respectively connected to points P1 to P3 when a voltage is supplied to the line L from the power source 300. As the capacitor C1 at the point P1 is located closest to the power source 300, the capacitor C1 is charged rapidly. The voltage of the capacitor C1 can therefore reach a required voltage V1 at time ta in a predetermined period from t1 to t2. As the capacitor C3 at the point P3 is located farthest to the power source 300, by way of contrast, the capacitor C3 demonstrates a charge characteristic of a gentle slope. Therefore, the voltage of the capacitor C3 cannot reach the required voltage V1 in the predetermined period from t1 to t2 but reaches it only at time tc.
This model can be applied to a liquid crystal device so that the liquid crystal device according to the related art has to face such a problem that a selected pixel cannot be charged to a predetermined voltage within a predetermined period.
The present invention is devised in the light of the above problems and has as an objective thereof the provision of an electro-optical device capable of charging a selected pixel to a predetermined voltage within a predetermined time period, a method of driving the electro-optical device and an electronic instrument.
According to a first aspect of the present invention, there is provided an electro-optical device for supplying a voltage to a plurality of pixels and charging the pixels to a predetermined voltage within a predetermined charge period, the pixels being formed of an electro-optical material and provided to correspond to intersections of scan lines and data lines, the electro-optical device includes a scan-line drive circuit which supplies a scan signal to each of the scan lines for selecting one of the scan lines; a data-line drive circuit which supplies a data signal to each of the data lines; and a voltage transformation circuit which changes a voltage of the data signal supplied from the data-line drive circuit based on a distance between the data-line drive circuit and one of the scan lines which has been sequentially selected by the scan-line drive circuit.
According to a second aspect of the invention, there is provided an electro-optical device for supplying a voltage to a plurality of pixels and charging the pixels to a predetermined voltage within a predetermined charge period, the pixels being formed of an electro-optical material and provided to correspond to intersections of scan lines and data lines, the electro-optical device includes a scan-line drive circuit which supplies a scan signal to each of the scan lines for selecting one of the scan lines; a first data-line drive circuit which supplies a first data signal to one end of each of the data lines; a second data-line drive circuit which supplies a second data signal to the other end of each of the data lines; and a circuit which causes the second data-line drive circuit to supply the second data signal to each of the data lines in synchronism with the supply of the first data signal to each of the data lines.
According to a third aspect of the present invention, there is provided an electro-optical device for supplying a voltage to a plurality of pixels and charging the pixels to a predetermined voltage within a predetermined charge period, the pixels being formed of an electro-optical material and provided to correspond to intersections of scan lines and data lines, the electro-optical device includes a scan-line drive circuit which supplies a scan signal to each of the scan lines for selecting one of the scan lines; a first data-line drive circuit which supplies a first data signal to one end of each of the data lines; a second data-line drive circuit which supplies a second data signal to the other end of each of the data lines; and a voltage transformation circuit which changes a voltage of the second data signal supplied from the second data-line drive circuit based on a distance between the first data-line drive circuit and one of the scan lines which has been sequentially selected by the scan-line drive circuit.